"As the father of four children, I am absolutely appalled that taxpayer dollars are being used to spread President Obama's socialist ideology. The idea that school children across our nation will be forced to watch the President justify his plans for government-run health care, banks, and automobile companies, increasing taxes on those who create jobs, and racking up more debt than any other President, is not only infuriating, but goes against beliefs of the majority of Americans, while bypassing American parents through an invasive abuse of power."

"The 'greatest good for the greatest number' applies to the number within the womb of time, compared to which those now alive form but an insignificant fraction. Our duty to the whole, including the unborn generations, bids us restrain an unprincipled present-day minority from wasting the heritage of these unborn generations. The movement for the conservation of wild life and the larger movement for the conservation of all our natural resources are essentially democratic in spirit, purpose, and method."

Yeah, it's easy: William Howard Taft. Taft is the one who lost faith in supporting the electorate. Taft is the one who decided that the only way to win re-election was money, and the only way to get money was to sell out to corporate interests. Without Taft's election, both parties might have maintained a somewhat progressive stance, at least through the 20s, and possibly prevented the depression (or at least kept it from getting so bad, as Europe still would have brought it on the world, regardless).
However, without Taft and the return of corporate-interests conservatism, the sequence of events that got us into WW1 so late might also have not happened. We could have either ended the war much sooner (possibly before the Russians had to pull out), or we could have lost as many men as the Europeans did over that long stretch. Both would have been world-changing occurrences.

Allow me.
First transition:
Roosevelt's Progressivism ---> Corporate interests: Reaction to trust-busting, then to 'new deal', loss of gold standard.
Corporate interests ---> Religious right/Today: It beings with the widening rich-poor gap and loss of constituency, much of remaining constituency in the south consisted of segregationists, so the party began to focus on religious rhetoric to expand the voting base. Along with preexisting corporate anti-communists, former Trotskyists and disillusioned socialists began to form the base of what are now known as "neocons". And so, the Party became an ironic mixture of corporatism, religious populism, and aggressive foreign policy. After the Bush administration and a prolonged series of 'moral' scandals, the Republican party lacked appealing leadership and intellectual foundation, so the constituency now listens to Fox News, Glenn Beck, Rush Limbaugh, Sean Hannity, and Ann Coulter for ideological guidance, guidance funded largely by, again, corporate interests.